In Algonquian languages, there are two subclasses of verbs whose syntactic transitivity is at odds with their morphological transitivity: AI+O and TI-O. This thesis examines these kinds of transitivity mismatches as they are found in the dictionaries of three different Algonquian languages: Munsee, Ojibwe, and Innu. Mismatch verbs play a crucial role in verb classification, forcing both the parsing apart of argument structure and verb agreement patterning and the recognition of the phenomenon of diachronic reanalysis from one class to another. Defined in terms of argument structure rather than verb agreement patterns, many AI+O and TI-O verbs can be attested in Munsee, Ojibwe, and Innu even if they do not form distinct classes on the basis of verb agreement in each language. From an overview of the range of semantic groups and patterns of stem morphology, each set of mismatch verbs can be understood as logical parts of the Algonquian verbal system. The stem morphology of AI+O verbs displays a lack of concern for their objects, which, as secondary objects, are generally unaffected themes rather than patients. TI-O verbs, meanwhile, are unergatives whose underlying transitive structure is apparent by the TI theme sign and patterning of medials. While this thesis is primarily a descriptive account of AI+O and TI-O verbs, it also offers a formal analysis of TI verbs and, in the process, refutes claims that AI and TI verbs form a single class.